Multiple element aerosol dispenser

ABSTRACT

AN AEROSOL MECHANISM PROVIDING SELECTIVE DISPENSING OF AEROSOL FORMULATION FROM A PLURALITY OF CONTAINER INTERIOR LOCATIONS.

United States Patent Norman Usen West Haverstraw;

Charles Edward Krachy, Buchanan, N.Y. 799,402

Feb. 14, 1969 June 28, l97l Union Carbide Corporation New York, N.Y.

inventors Appl. No. Filed Patented Assignee MULTIPLE ELEMENT AEROSOL DISPENSER 19 Claims, 6 Drawing Figs.

US. Cl 222/129, 222/394, 222/40219 Int. Cl B6511 83/06 Field of Search 222/l29, 394, 4021-40225 References Cited UNITED STATES PATENTS 5/l957 Samuel 3,209,960 lO/l965 Green 3,447,55l 6/1969 Braun Primary Examiner-David M. Bockenek Attorneys- Paul A. Rose, John F. Hohmann and Alfred Musumeci ZZZ/402.19 222/402. 17X 222/402.24X

ABSTRACT: An aerosol mechanism providing selective dispensing of aerosol formulation from a plurality of container interior locations.

PATENTEnJuN28l9n 3587.929

ENTORS N0 N USEN CHARLES EDWARD KRACH) ATTORNEY MULTIPLE ELEMENT AEROSOL DISPENSER The present invention pertains to aerosol-dispensing systems and more particularly to a valve arrangement which permits dispensing of aerosol formulation from differing locations within the container.

Aerosol-dispensing systems usually comprise a container storing aerosol formulation, a valve structure mounted within the container including a valve stem extending exteriorly of the container through which aerosol formulation is dispensed, and an actuator assembly mounted atop the container to actuate the valve stem. Many aerosol-dispensing systems presently in use require a diptube extending from the valve structure to the bottom of the containerdue to the fact that they are held in an upright position while aerosol formulation is dispensed therefrom. The diptube provides a dispensing flow path from a single location within the container at the bottom thereof, thereby enabling continuous dispensing even when the quantity of aerosol formulation within the container is at a reduce level.

In many aerosol applications, it would be desirable and advantageous to enable selective dispensing of aerosol formulation from a plurality of different locations within the container. Such a capability would provide increased versatility and convenience in connection with many specific applications. For example, it would be possible to provide a dispenser which would operate effectively in either an upright or inverted position with aerosol formulation flowing from the upper section of the container when held in the inverted position. Such a system would involve selective dispensing of aerosol formulation from two locations within the container; that is, aerosol formulation would flow from the bottom of the container when in an upright position and from the top when in an inverted position.

An additional, potentially more significant application for such a capability is in connection with a system for dispensing a variety ofdiffering aerosol formulations or ingredients. With a system which enables dispensing from differing locations, compartmentalization of a container structure whereby storage of different aerosol ingredients could be accomplished could enable utilization of such a system to selectively dispense any one of a variety of ingredients from a single dispensing assembly. Thus, a unitary aerosol dispenser could be equipped to permit a user to select and dispense any one of a plurality of ingredients, with the selection process involving merely actuation of a selecting mechanism, such as rotation or dialing of an actuator cap.

Accordingly, it is an object of the present invention to provide an aerosol dispenser enabling selective dispensing of aerosol formulation from a plurality of locations within a container.

Aerosol-dispensing systems may generally be classified in two operative categories; a first being a system wherein aerosol formulation is dispensed in a continuous stream, and a second being a system wherein dispensing is provided in a predetermined metered amount with each separate actuation of the dispensing structure permitting discharge of only one dose of said predetermined metered amount. The basic structural difference between the systems resides in the valve assembly, and it is usually the structural nature and configuration of the valve assembly which determines whether a particular system shall be a metered system or a continuous flow system. In the construction of an aerosol-dispensing system embodying the principles of the present invention, it would be of significant advantage to provide an approach that is adaptable for use with both the metered system and the continuous flow system.

Accordingly, it is a further object of the present invention to provide an aerosol-dispensing system enabling dispensing of aerosol formulation from a plurality of locations within a container which is adaptable for utilization with either a metering aerosol dispenser or a continuous flow aerosol dispenser.

A further factor of significance in connection with this invention relates to the type of aerosol formulation which is to be dispensed. Generally speaking, aerosol formulation consists of an active material and a propellant material which operates to provide the moving force to transport the active material from the container interior to the point of ultimate application. Although the present invention is deemed useful with a wide varietyof aerosol formulation types, it is considered particularly adaptable for use with a dry powder aerosol system described and claimed in U.S. Pat. No. 3,081,223 issued Mar. 12, I963 to P. E. Gunning and D. R. Rink and assigned to the same assignee as the present invention. This dry powder system comprises an aerosol formulation which involves a self-propelled powder delivered from a pressurized container in a dry spray substantially liquid-free. This dry powder system comprises a free-flowing powder composition which constitutes the active material to be dispensed from the container. At least one component of the powder composition comprises particles of a liquid propellant-sorbent material, with a vaporizable liquid propellant being held in said sorbent material under the vapor pressure of the propellant normally existing in the container at ambient temperature. Upon exposure of the aerosol formulation to the ambient environment externally of the container, the propellant is vaporized by reducing the pressure to which it is exposed. The dry powder system contemplated herein comprises a threephase system including a vapor phase and a homogeneous, free-flowing powder composition, the latter containing a vaporizable propellant. The powder composition which constitutes a major portion of the system provides the supporting phase. Thus, an important aspect of the dry powder system pertinent to its utilization with the present invention relates to the fact that the powder is the supporting phase thereby providing an aerosol formulation wherein the propellant is distributed throughout the active material with each component of the active material having sorbed thereon and carrying its own propellant material.

Accordingly, it is a further object of the present invention to provide an aerosol-dispensing system enabling dispensing of aerosol formulation from a plurality oflocations within a container which is particularly adaptable for use with a dry powder aerosol formulation.

A better understanding of the present invention may be had by reference to the following detailed description of a preferred embodiment thereof taken in connection with the accompanying drawing wherein:

FIG. 1 is a cross-sectional view of an aerosol-dispensing structure embodying the principles of the present invention;

FIG. 2 is a view in perspective of the upper portion of the structure of FIG. 1;

FIG. 3 is a cross-sectional view partially broken away of an alternative embodiment of the present invention;

FIG. 4 is a cross-sectional view taken along the line 4-4 of the valve stem shown in FIG. 3;

FIG. 5 is a cross-sectional view partially broken away of a second alternative structure embodying the principles of the present invention; and

FIG. 6 is a cross-sectional view depicting another alternative embodiment of the present invention.

Referring now to the drawing, and particularly to FIG. 1 thereof, there is shown an aerosol valve assembly comprising a valve housing 10 and a valve stem 12 both formed of molded plastic material, together with a sealing gasket 14 and spring means 16 interposed between the valve housing 10 and the valve stem 12 urging the valve stem 12 against the sealing gasket 14.

A mounting cup 18, which is integrally formed with or firmly mounted to an aerosol container (not shown) in a manner well known to those skilled in the art, comprises an indentation 20 which engages a shoulder 22 of the valve housing 10 thereby to firmly mount together the valve housing 10 and the mounting cup 18. The sealing gasket 14 is annularly shaped and comprises an appropriate resilient material, such as Buna N rubber, having therein an opening 24 through which the valve stem 12 extends. The sealing gasket 14 is maintained in tight engagement between the upper face 26 of valve housing and a horizontal wall 28 of mounting cup 18. With the assembly in the nondispensing position, the spring means 16 engages the underside of an annular protuberance 30 and presses the upper side of said annular protuberance against the wall of opening 24 in gasket 14. The pressure of spring means 16 effects a sealing engagement between the valve stem 12 and the sealing gasket 14 thereby preventing escape of aerosol formulation from within the container. The lower end of spring means 16 engages an annularly shaped bottom gasket 31 which is seated within the housing 10 as shown.

A retaining collar 32 is mounted exteriorly of mounting cup 18 by means of an annular-claw portion 34 which engages the indentation of mounting cup 18. The retaining collar 32 includes an annular hub portion 36 which includes an opening 38 therein through which the upper section of the valve stem 12 extends.

The retaining collar 32 may have formed on the underside thereof a recess 40 which serves to retain in position a lubricating washer 42 which will provide lubrication between the valve stem 12 and the sealing gasket 14 thereby avoiding overly tight frictional engagement therebetween without impairing the sealing function thereof. The inclusion of lubricating washer 42 is optional and forms no part of the present invention.

Aerosol formulation is dispensed through the system by permitting the aerosol formulation to flow from the interior of the container (not shown) to a chamber 44 defined by the valve housing 10. With the chamber 44 filled with aerosol formulation, depression or downward movement of the valve stem 12 will expose to chamber 44 a discharge orifice 46 formed in the upper portion of valve stem 12. With the valve stem 12 depressed against the force of spring means 16 to a point where discharge orifice 46 is located below sealing gasket 14 and exposed to chamber 44, aerosol formulation will flow from chamber 44 through discharge flow means which include discharge orifice 46 and an internal conduit 48 defined within the valve stem 12 from which it may be dispensed to the external atmosphere.

Ofcourse, it is assumed that a suitable actuator (not shown) will be mounted atop the container engaging the valve stem 12 to permit appropriate actuation thereof by a user.

As previously stated, the principal object of the invention is to provide dispensing from a plurality of locations within a container, with one specific application relating to a system which will dispense in either the upright or inverted position. The structure of FIGS. 1 and 2, which relate to an embodiment wherein dispensing is enabled from two locations within the container, depicts a mechanism for operation in either the upright or inverted position.

The major portion of the mechanism whereby operation in an upright or inverted position is enabled is located at the lower end of the valve system. Valve housing 10 comprises in the lower end thereofa cylindrical opening 50 into which the bottom portion of the valve stem 12 extends. The cylindrical opening 50 extends to the bottom of the valve housing 10 and is exposed to the container interior. The lower portion of the valve stem 12 engages the sides of the opening 50 in sliding relationship thereby providing lateral support for the valve stem 12 while enabling appropriate axial movement thereof.

The valve housing 10 also comprises conduit means comprising a plurality of branches through which aerosol formulation may flow into the chamber 44. In the embodiment shown, the conduit means comprises two branches, conduit 52 located within a diptube 54 which extends to the bottom of the container, and a second branch comprising conduit 56 defined by the housing 10 which extends from the outer sidewall of valve housing 10 to the upper portion of opening 50. It is intended that when the aerosol dispenser is in the upright position, aerosol formulation will flow into the chamber 44 through the conduit 52. When the dispenser is in the inverted position, aerosol formulation flow into the chamber 44 is enabled by the conduit 56. The mechanism whereby this manner of operation occurs includes the specific configuration of the lower portion of the valve stem 12 which, as shown in FIG. 1, comprises an indentation 58 which is axially aligned with a vertical rib 60 located at the upper end of the valve stem 12. As shown in FIG. 2, the vertical rib 60 cooperates with the opening 38 in hub portion 36 in a manner whereby the valve stem 12 may be rotated and held to one of two angular positions with the rib 60 engaging either an oblong end 62 or an oblong end 64 of opening 38. Rotation of the valve stem 12 between these two positions is enabled due to the fact that the retaining collar 32 and its hub portion 36 are formed of pliant plastic material which, while holding the valve stem 12 in either of two positions with the rib 60 engaging the oblong end 62 or 64, will also permit rotation thereof by application of a rotational force to cause deformation by rib 60 of a portion of the material defining the opening 38 to permit movement of the rib 60 between oblong ends 62 and 64.

In the operation of the device, a decision is first made whether the dispenser is to be operated in the upright or in the inverted position. lf operation is to be in the upright position, stem 12 must be in the position indicated in the drawing in FIGS. 1 and 2 with the vertical rib 60 being engaged within oblong end 62 and with indentation 58 facing toward conduit 52 of the diptube 54. With the dispenser in the upright position, all of the aerosol formulation will be at the bottom of the container. Accordingly, conduit 56 will be exposed only to the head space while conduit 52 is in direct communication with the mass of aerosol formulation thereby enabling flow through diptube 54 and through the cavity or bypass provided by the indentation 58 into the chamber 44. It will be noted that the side of the valve stem 12 opposite the indentation 58 overlies conduit 56 blocking flow therethrough and permitting flow from the container to the chamber 44 to take place only through the diptube 54. Accordingly, it will be clear that the surface of valve stem 12 must be in sealing contact with the surface of cylindrical opening 50, to block flow of aerosol formulation through either conduit 52 or 56, as well as being in sliding engagement therewith.

With the valve stem 12 in the position shown in FIG. 1, aerosol formulation will occupy the chamber 44 and upon depression or actuation of the valve stem 12 the indentation 58 will be lowered from the opening of conduit 52 when the discharge orifice 46 is lowered into flow communication with chamber 44. If the dispensing device is intended to operate as a metering valve, the indentation 58 should be configured as shown in FIG. 1 so that upon lowering the valve stem 12 to the dispensing position, the indentation 58 will be below the opening to conduit 52 with the portion of the valve stem 12 immediately above the indentation 58 being placed in position to block further flow through conduit 52. In this manner, both conduit 52 and conduit 56 will be blocked and only the amount of aerosol formulation present within the chamber 44 will be dispensed. With this type of construction, each time the valve stem 12 is raised and lowered the chamber 44 will fill with aerosol formulation and there will be dispensed only a measured amount determined by the volume of chamber 44.

However, if it is desired to operate the dispenser as a continuous flow system, then the indentation 58 must be elongated to conform to the dotted version depicted in FIG. 1 and labeled 580. With the indentation elongated as at 58a, depression of the valve stem 12 to a position where discharge orifice 46 is in flow communication with chamber 44 will not cause lockage of conduit 52 since indentation 580 will continue to provide a bypass cavity permitting continued flow from the container through conduit 52 to chamber 44 and through discharge orifice 46 to conduit 48 and to the outer atmosphere. In this version of the device, each time that the valve stem 12 is depressed, flow will continuously occur as long as the valve stem 12 is maintained in the depressed condition and flow will be terminated when valve stem 12 is released permitting the spring means 16 to raise the valve stem blocking flow through discharge orifice 46.

When it is desired to operate the dispenser in an inverted position, it becomes necessary to rotate the valve stem 12 to a position where the vertical rib 60 will coincide with oblong end 64 of opening 38. This will place the indentation 58 at the opening of conduit 56 while the opposite side of the valve stem 12 will block flow through conduit 52. It will be clear that with the container in the inverted position, all of the aerosol formulation therein will be brought to the end of the container at which the valve assembly is mounted; that is, to what would normally be the upper end with the container in the upright position. With the container in the inverted position, conduit 56 will be adjacent the mass of aerosol formulation and flow will occur from the container through conduit 56 past the cavity defined by indentation 58 and into the chamber 44. The operation of the valve system in connection with the dispensing operation is identical with that previously described and metered flow will be provided with the indentation 58 configured as shown whereas continuous'flow may be effected by elongation of indentation 58 to the dotted version shown as 58a. Once again, axial movement of the valve stem 12 to place the discharge orifice 46 in flow communication with the chamber 44 will cause the aerosol formulation to be dispensed in the manner previously described.

If the device is to be structured in a continuous flow arrangement with the elongated indentation 58a, some precautionary measures must be taken in order to avoid operating the dispenser in the wrong position. For example, if the valve stem 12 were positioned with the indentation 58a turned toward the conduit 56, and the valve stem 12 depressed with the dispenser in the upright position, this would vent the head space within the container to the outer atmosphere without providing an appropriate flow path for the active ingredient of the aerosol formulation. Under such circumstances, there would occur significant loss of the propellant material without discharge of the active ingredient, and such loss could be sufficient to render the dispenser inoperative. The opportunity for occurrence of sucha situation could readily be significantly reduced by precautions, such as clear labelling of the actuator to insure that depression of the valve stem 12 occurs only with the indentation 58a in the proper position relative to the position of the dispenser.

The proximity of conduit 56 to mounting cup 18, or to the top of the container, will be significant since, if placed closer together, there will be a tendency to enable dispensing flow in the inverted position at a lower level of depletion of aerosol formulation. If the conduit 56 and the mounting cup 18 are placed further apart, it will require that a greater amount of aerosol formulation be present within the container sufficient to reach the opening of conduit 56 when the container is in the inverted position to permit flow. Alternatively, a diptube such as diptube 54 may extend from the opening of conduit 56 to the upper, or mounting cup, end of the container thereby tending to decrease the amount of aerosol formulation left within the container as waste when the dispenser ceases to function.

In structuring the device of the present invention, certain dimensional limitations should be noted. For example, the bottom end of the vertical rib 60 must be located a sufficient distance above the lubricating washer 42 to prevent interference with the down stroke of the valve stem 12. At the same time, the rib 60 must be positioned to engage the ends 62,64 of opening 38 when the stem 12 is in the uppermost position and, accordingly, the lower end of the vertical rib 60 must not extend to above the hub portion 36 on the upstroke ofthe valve stem 12. Additionally, it is important in mounting the retaining collar onto the mounting cup 18 to insure that the retaining collar does not rotate or is not movable relative to other parts of the assembly. This is particularly important due to the fact that'the relative positioning between the retaining collar 32 and the valve stem 12 will determine whether the dispenser is adjusted for inverted or upright use. In order to insure tight engagement of the retaining collar onto the mounting cup 18, a cement may be applied between the members or the members may be crimped in a manner well known to those skilled in the art to prevent relative rotation therebetween.

It will be apparent that in the assembly of the device it is necessary to appropriately align valve housing 10, valve stem 12 and retaining collar 32. This alignment is necessary because the relative positioning between vertical rib 60 and the oblong ends 62,64 must be correlated with the relative position between indentation 58 and the conduits 52 and 56. Such relative alignment can be easily accomplished in a number of known ways, for example; by applying an appropriately placed marking on each of the parts so that proper alignment of the marking will effect appropriate alignment of the parts. Furthermore, in the finished product appropriate for consumer use, markings may be applied to indicate the relative rotational positioning of the parts which will enable upright or inverted use. For example, an actuator cap (=not shown) may be mounted upon the upper end of valve stem 12 with application thereto of markings identifying the position of the valve stem which will enable upright or inverted use.

A further significant structural and operational aspect of the present invention relates to the engagement of the lower end of valve stem 12 with the cylindrical opening 50. As previously stated, it is necessary to provide an effective sealing contact between the surface of valve stein l2 and the surface of opening 50 to enable selective blocking of flow between interior portions of the container and chamber 44. The necessity for such sealing engagement may cause binding or sticking of the valve stem 12 within the opening 50 thereby impeding its upward movement in returning to the nondispensing position. FIGS. 3, 4 and 5 depict structural expedients for overcoming and avoiding interference with axial movement of valve stem 12.

FIGS. 3 and 4 depict a structural embodiment of the present invention whereby interference between a valve stem 12a and the surface of opening 50 is overcome by diminishing the surface area contact between the two members. This is accomplished by fluting the bottom of the valve stem. As shown in FIGS. 3 and 4, the lower portion of valve stem 12a is formed with three flutes 66, 68 and 70. These flutes are formed by forming concavities 67, 69 and 71 at the lower end of the valve stern 120. It will be apparent from FIG. 4 that at the fluted end of the valve stem 12a the only surface area in frictional engagement with the opening 50 will be along the outer surfaces of the flutes 66, 68 and 70, there being no surface contact between the concavities 67, 69, 71 and the surface of opening 50. Accordingly, by fluting the valve stem, contacting surface areas are significantly reduced and frictional interference with vertical movement of valve stem 12a is significantly overcome. Despite the fact that surface contact is reduced in this fashion, the surface contact which does exist between the valve stem 12a and the opening 50 is sufficient to provide the required sealing engagement.

An alternative approach to overcoming excessive frictional engagement between the valve stem and the opening 50 is depicted in FIG. 5. The basic concept of this alternative involves the addition of a lower spring means 72 positioned between the valve housing and the lower end of the valve stem. As shown in FIG, 5, a valve housing 10b is slightly restructured from the configuration of the housing 10 to include an opening 50a of reduced diameter cooperating with a larger diameter opening 50b to provide therebetween a lip 51 upon which the lower end of spring 72 rests, with the diameter of the opening 50a being smaller than the outer diameter of the spring while the diameter of the opening 50b is sufficient to permit placement therein of the spring 72. The lower end of a valve stem 12b is slightly modified to include a protuberance 74 which fits within the upper end of the spring means 72 thereby maintaining an axial alignment between the valve stem 12b and the lower spring means 72. The lower spring means 72 is held in compression between the valve stem 12b and the lip 51. Downward movement of the valve stem I2b tends to compress the spring which will exert a reaction force tending to drive the valve stem 12b upwardly. The force of the compressed spring 72 will tend to overcome any frictional engagement between the outer surface of the valve stem 12b and the opening 50b.

An additional expedient to provide proper stem movement is a lubricating washer 73 positioned between the stem 12b and the spring means 72. The washer 73 may be formed offelt or other suitable material impregnated with a lubricant which will be applied to the walls of opening 50 each time that the stem 12b is actuated, thereby to apply lubricant coating between stem 12b and opening 50.

In the actual construction of an embodiment of the present invention either or both of the expedients described to overcome the frictional force at the lower end of the valve stem may be utilized. That is, it is possible to provide not only a fluted lower end for the valve stem, but also in combination therewith a spring means operating similar to spring 72. However, the preferred embodiment of the present invention would be to utilize the structure depicted in FIG. in conjunction with a system which would operate in the manner described and depicted in FIGS. 1 and 2.

As previously stated, the present invention may provide flow from a plurality of locations within a container in excess of the two previously described herein. This could be accomplished by providing a corresponding number of branches to the conduit means similar to the branch provided by diptube 54. An example of such a structure is depicted in FIG. 6, which involves, in essence, addition to the valve housing of a plurality of diptubes similar to diptube 54 circumferentially spaced around a valve stem 12b. in H6. 6, there is shown a system involving four branches. However, a different number could readily be provided. As shown, a valve housing 10c has mounted therein four diptubes 76, 78,80 and 82, each providing a separate conduit to the surface of an opening 50c formed within the valve housing 10c. A valve stem 12b comprising an indentation 58b operates in a manner similar to that previously described to control flow of aerosol formulation. Rotation of the valve stem 12b to an appropriate position will block flow through three of the four conduits shown and permit flow through the conduit in alignment with indentation 58b which, in the situation shown in FIG. 6, would be the conduit formed by diptube 82.

As previously stated, a system similar to that shown in FIG. 6 could be utilized with a compartmentalized container to provide selective dispensing of one ofa plurality of aerosol formulation active ingredients. On such a structure, each compartment of the container could contain a different ingredient with one diptube, e.g., 76, 78, 80 or 82, extending in flow communication to each compartment.

We claim:

1. An aerosol-dispensing system comprising a container storing aerosol formulation to be dispensed, valve means actuated between a dispensing and a nondispensing condition, discharge flow means controlled by said valve means for effeeting flow of aerosol formulation from within said container to exteriorly thereof, conduit means located internally of said container and including a plurality of branches arranged to communicate with said valve means, each of said branches providing a flow path for aerosol formulation between a location within said container and said discharge flow means, each of said branches providing said flow path from a different location within said container, and means capable of selectively blocking aerosol formulation flow through said branches for determining which of said branches will be in flow communication with said discharge flow means.

2. A system according to claim 1 wherein said blocking means are selectively controlled by direct manipulation from exteriorly of said container.

3. A system according to claim 1 wherein said blocking means are selectively operable irrespective of gravity forces thereon.

4. A system according to claim 1 wherein said blocking means are formed by structural adaptation of said valve means.

5. A system according to claim 1 including means comprising a location externally of said container providing an indication of the position of said blocking means relative to said branches.

6. A system according to claim 1 comprising means externally of said container constraining said blocking means to particular positions relative to said branches but permitting displacement thereof from one ofsaid positions to any other.

7. A system according to claim 1 comprising metered flow dispensing of aerosol formulation.

8. A system according to claim 1 comprising continuous flow dispensing of aerosol formulation.

9. An aerosol-dispensing system comprising a container storing aerosol formulation to be dispensed, a valve housing firmly mounted to said container and defining a chamber therein, a valve stem extending from within said chamber to the exterior of said container and comprising flow means for effecting discharge of aerosol formulation, means mounting said valve stem in sealing engagement with the interior of said container and permitting movement thereof to effect discharge of aerosol formulation from within said chamber through said discharge flow means, conduit means arranged to communicate directly with said valve stem and extending in flow communication between said chamber and a plurality of different locations within said container, and means on said valve stem for selectively blocking flow through said conduit means irrespective of gravity forces thereon.

10. A system according to claim 9 wherein said valve stem is movable to a plurality of positions each correlated to one of said locations within said container whereby placement of said valve stem will determine the location from which aerosol formulation will be dispensed.

11. A system according to claim 9 wherein said conduit means comprise a plurality of branches each terminating proximate said valve stem, said valve stem comprising a surface configuration adaptable for blocking flow through said terminations and bypass means enabling flow between said terminations and said chamber.

12. A system according to claim 11 wherein said blocking surface and said bypass means are relatively positioned on said valve stem in a manner whereby rotation of said valve stem will selectively control flow through the branches of said conduit means.

13. A system according to claim 11 wherein said bypass means comprises an indentation in the surface of said valve stem.

14. A system according to claim 9 comprising indicating means mounted on said valve stem externally of said container and positioned relative to said blocking means providing an indication ofthe flow through said conduit means.

15. A system according to claim 11 wherein said indicating means comprise a rib axially aligned with said bypass means.

16. A system according to claim 15 comprising means mounted upon said container releasably engaging said rib to constrain rotational movement of said valve stem thereby tending to maintain said bypass in a desired alignment with said conduit means.

17. A system according to claim 9 comprising a cylindrical opening defined by said valve housing slideably engaging said valve stem in sealing contact therewith, said conduit means having terminations at the surface of said cylindrical opening, said valve stem being indented to provide a bypass flow path between said terminations and said chamber whereby rotation of said valve stem to selectively align said indentation with said terminations determines locations communicating through said conduit means with said chamber from which aerosol formulation is to be dispensed.

18. A system according to claim 13 wherein the axial length of said indentation determines whether said system is to operate as a metered or continuous flow system.

19. A system according to claim 17 comprising means associated with said valve stem at a location in noninterfering relationship with said conduit means to overcome undue friction between said cylindrical opening and said valve stem thereby to avoid impedance of axial sliding movement of said valve stem. 

